1. Field of the Invention
The present invention relates to structural supports, and particularly to a system for selectively enhancing the support configuration of cantilever beams on jack-up drilling units or the like.
2. Description of the Relevant Art
A major limitation with oil well drilling or work over activities involving jack-up units utilizing a platform jacket and cantilever beam is the reduced drilling load available, due to the outreach position of said cantilever beams.
In such systems, the drill-floor that carries the drilling derrick is typically supported by 2 independent beams via a substructure that forms the cantilever assembly. The drill-floor skids transversely, to reach the drilling template ports, and as a result of this movement, the drilling load is applied unequally on the two cantilever beams. Thus, maximum outreach and offset of the drill-floor are dictated by the allowable load limits of the beams.
To assist the operator, a chart specific to every vessel indicates the position of the floor in relation with the allowable drilling load, and on average, the maximum drilling load is achievable over a limited portion of the drilling envelope. Generally, when drilling over a platform jacket the cantilever works at a far outreach only where the drilling load is reduced.
Accordingly, the reduced drilling loads impose limitations on operations, the greater extent maximum drilling load being achievable only within the pre-established drilling envelope. Self elevating platforms (jack-ups) which have good load chart capabilities surely are preferred by operators in a competitive market.